ludeowner

Hi guys,

I need to buy a few miscellaneous parts to prepare for my M2 DP install. One of the things I was gonna be getting are a few M10-1.5 x 25mm bolts to replace the studs.

I had a question about what style bolt to use though. Someone mentioned using a socket head cap screw. Is there a special reason I would want to use that type of bolt as opposed to a regular hex type bolt? I just wanted to make sure that I dont specifically have to get a socket head screw. I dont want to have to buy the correct sockets to tighten it down too.

Also just another question...I will be soaking the DP bolts in WD40 for a few days before the install. Then on the day of the install I will use some CLP "break free". But if the studs still break, I just wanted to know how long (on average) it will take to remove the turbo assembly? how many of you guys had to take off your turbos because a stud broke? and how long did it take you to remove the turbo, remove stud, and reinstall the turbo?

thanks

SOCKET HEAD CAP SCREW

1st to 3rd

Hex heads are usually too big. They hit the welds on the pipe, at least they did on mine.

rotary-tt

Spend the bucks to get the Mazda studs and nuts. Well worth the $$ IMHO. I had nothing but trouble trying to use aftermarket studs and nuts...

IRPerformance

iTrader: (41)

Don't use those. They are easier to strip and then you're screwed. I did a motor swap on an S2000 and stupid Honda used those on the drivehshaft. Very easy to strip. You need some low profile14mm nuts. They can be difficult to find though. There is enough room to get a socket on all but one off the bottom nuts. For that you I just use an open ended wrench,

ludeowner

thanks for the replies guys,

1st to 3rd,

Good call, I did notice that 2 of the 4 holes on the DP are close to the welds.

rotary-tt

I will consider he OEM studs and bolts if the price is right.

Rotary Experiment Seven,

Hmm, I think I will just go with a set of hex bolts then. I dont want to possibly end up with some stripped socket head bolts.

thanks

911GT2

I agree about the not using socket head cap screws. Just go with regular hex head bolts if you're changing from the studs and nuts.

I soaked mine overnight in liquid wrench. WD-40 is good stuff, but liquid wrench is quite a bit stronger. This will also help in not snapping a stud. I didn't snap any of the studs from my turbo manifold, but I did snap one from the cat.

ludeowner

Ohhhh, that reminds me. What do most people do about their cat studs? cause I have also heard of people having trouble getting those off and breaking them too.

I didnt pay much attention to the cat flange when I had the car up on a lift, but does it have a nut integrated into the cat flange or something? What bolts or studs or whatever would I have to use if those break on me? I dont wantto go with OEM unless I abolutely have too, I want to just pick up the correct cat stud replacement bolts from NAPA (if htey have them).

Thanks

911GT2

There is a flange on the end of the cat with a stud screwed into it. And a flange on that end of the downpipe that will fit over the stud. And a nut goes on the other side of the dp flange to secure it.

When mine snapped I took the car down to meineke and had them heat the hell outta the stud and pull it out with vise grips. They put a regular SS nut and bolt back on in place of that stud, but the other stud stayed intact. I haven't a clue what the measurements are on those studs.

Another thing I just thought of though. The gasket between the cat and the dp is paper, and should probably be replaced. I replaced the turbo manifold gasket too, but that ones metal and might be ok.

ludeowner

Does the stud have a body with raised grooves all the way around? and the cat flange has grooves in the hole which mesh up with the stud grooves to keep it from turning?

I remember when I was installing an aftermarket catback on my Prelude the stock studs did not want to come out. I tried hitting them out with a hammer with all my might but they wouldn't budge. I applied some lubricating oil, waited a minute and I barely tapped on the stud and they fell out. I'm hoping the same thing will happen with my FDs cat studs.

I'll just bring my DP into NAPA with me and a few nuts and bolts big enough to go through the lower DP holes. And about the cat flange gasket, that was one of the things on my shopping list. But I was gonna hold off on the turbo gasket since they are expensive as ****!

911GT2

Yes. The stud actually screws into the cat flange. The pre-cat and dp flanges are not threaded, and just slide over the other end of the stud.

The turbo manifold gasket was $49 I think form Mazda. It needed to be ordered though so give yourself like a week or so for delivery time on that.

ludeowner

Opps I meant to say M10x1.5x42mm for the replacement bolts. I am pretty sure that is the correct size.

dgeesaman

iTrader: (7)

I bought some high-quality Socket Head Cap Screws in 316 Stainless of that size. You probably won't find a screw/nut that has a significantly smaller head size. Don't use an allen key to drive it - get the allen head rachet drive for your socket wrench.

Worked like a charm. Slightly shorter would probably be a good idea though - it will give you plenty more room to get them threaded in.

Dave

1st to 3rd

The stock studs/nuts wouldn't fit mine. Well, they physically fit, but 1 or 2 hit the edge of the weld and wouldn't sit flat. I don't have a M2 pipe, so I don't know if they have additional clearance. Regular hex bolts have larger heads, so those are def. out.
I don't know why you wouldn't use cap screws. I think they are much more difficult to strip then regular bolts... as long as you are using the correct drive.

ExpensiveHobby22

Buy some PB blaster. It's better than liquid wrench. You can find it at most auto parts stores. You can also get the exhaust gaskets directly from racing beat. That's what I did. They were cheaper than directly from Mazda too.

ludeowner

Hey guys,

I just got back from getting parts...with the M2 DP there seems to be a slight clearance issue with the rear-lower bolt hole. I cant get a hex bolt in the hole...I may have to grind away some of the metal around the bolt opening, but that's not a big deal.

I also found some PB blaster at teh NAPA store. That stuff was a lot easier to find that I thought. So on the days before I do the install I will soak the DP bolts with the PB. But in the event that the one of the precat studs break on me, I'd still want to know how involved the turbo removal is.

How long did it take you first timers take to remove the precat studs?

thanks

ExpensiveHobby22

I got lucky. All mine came loose really easily. I soaked them in pb blaster for 3 days before I tried to pull them, but I suspect the fact that the engine had only been in the car for the year is what made it really easy.

One thing that works for getting the dp in easier is unbolting the passenger side engine mt under the frame and jacking that side up a bit. Make sure you find a safe place to jack it up by though.

ludeowner

Ackkk!!!

what I meant to say was how long did it take you guys to remove the turbo assembly.

Thanks

BigIslandSevens

iTrader: (4)

Give yourself a weekend to do it. You should have no trouble if you soak everything and take your time. I just took a pair off today . It took me about 2.5 hours to get them off. You will want to replace some extra gaskets if your going that far. Oil return line gaskets (4-5), coolant hoses to turbos(2), any vaccum hoses that look suspect,(remember the pills if you replace those hoses),All exhaust gaskets since your there!,(Malloy Mazda has a manifold gasket kit for around $100.It includes the intake manifold to engine, lower to upper man. gasket, both exhaust manifold to engine gaskets Talk to Ray Crowe) , also get the turbo to manifold gaskets(2), y-pipe gaskets(4), {this includes the intake elbow gaskets}, y-pipe o-ring(1), and any of those studs and nuts that are suspect. Sounds like alot, but you only want to go there once!!! PM me with any specific questions. I just did it 30 mins. ago!!! Good luck. P.S. Those allen socket style studs scare the bejesus out off me!!! They strip out easier than Pam Anderson! Spend the dough for OEM or find a hex bolt that fits. Just my opinion though. I've seen tons of those strip and i have the correct tools!